Trace AidBy Greenwald, Elliot; Zilber, David; Goldberg, Richard; NSF 2008 Engineering Senior Design Projects to Aid Persons With Disabilities, pp. 254-255
Publication Date: 2011
Description of a device that aids children with autism in the development of handwriting skills. The Trace Aid includes a photodiode sensor mounted in the tip of a pen which the student uses to trace over a piece of paper with a large printed letter. The paper rests on top of a commercial light bed with a checkerboard pattern. Light shines up from the bed, through the paper, and the light level is detected by the photodiode sensor. When the sensor is over a dark area on the page, the black ink on the paper blocks a significant amount of light, resulting in a low voltage output from the photodiode. When the sensor is over a blank area of the page, more light reaches the sensor and its output voltage increases. When the user is properly tracing over the checkerboard patterned tracing area, the photodiode signal is sinusoidal. A microcontroller looks for a sinusoidal signal of a certain minimal frequency, and triggers a musical feedback accordingly. As long as the pen is moved over the tracing area, music is heard from the audio output. The Trace Aid is built into a commercially available children’s tracing toy. The inking cartridge is from a commercial ballpoint pen. The pen connects to the circuitry via a cable and audio stereo plugs. Commercial, external speakers and headphones provide the audio feedback. The Trace Aid was developed by biomedical engineering students at University of North Carolina at Chapel Hill at a cost of 205 dollars.
Published by: Creative Learning Press, Inc. (Website:http://www.creativelearningpress.com)
Link to text: http://nsf-pad.bme.uconn.edu/2008/Chapter%2013,%20University%20of%20North%20Carolina.pdf